Means for optically aligning motion-picture projectors



y 1953 w. c. RICORD, SR 2,639,513

MEANS FOR OPTICALLY ALIGNING MOTION-PICTURE PROJECTORS r Filed Feb. 21,1950 INVTOR. is 44 36 MAM/P0 Cfi/co/m Se Patented May 26, 1953 UNITEDSTATES PATENT OFFICIE MEANS FOR OPTICALLY ALIGNING MOTION-PICTUREPROJECTORS 6 Claims. 1

This invention appertains to a novel and practical means for effectingthe accurate alignment of the light projecting components on the opticalaxis of a motion picture projector having its light source comprised ina fixed carbon electrode and a relatively adjustable carbon electrodedisposed in axial alignment with the light projecting components andwith each other, in order that maximum lumens of light,

generated by the light source, will impinge the picture viewing screen.

For the attainment of this and other objects of equal importance, theinvention resides in the certain new and useful combination,construction, and arrangement of parts, as will be hereinafter morefully described, set forth in the appended claims, and illustrated inthe accompanying drawings, wherein:

Figure 1 is a schematical view of the light projecting components of amotion picture projector and showing the cooperative association ofparts to accomplish the objects and purposes of the invention;

Figure 2 is a front side elevation of a circular member, constituting amounting for one end of the sighting element extending axially betweenthe centers of the reflector and the lens housing, the same to beremovably mounted in the center of the reflector, upon the removal ofthe fixed carbon electrode therefrom;

Figure 3 is a sectional view, taken through the line 33 on Figure 2,looking in the direction of the arrows;

Figure 4 is a perspective view of a shuttle to be mounted in theadjustable carbon electrode holder of the projector, upon the removal ofthe adjustable carbon electrode therefrom, for the passage of thesighting element through the axial bore thereof;

Figure 5 is a top plan view of a bracket to secure the adjustable carbonelectrode holder, and consequently the shuttle, rigidly in a setposition during the aligning operation;

Figure 6 is a side elevation of a gauge plate to be cooperativelyassociated with the film aperture of the projector;

Figure '7 is a sectional view, taken through the line 'l-'! on Figure 6,looking inthe direction of the arrows;

Figure 8 is a face view of an aperture element to be frictionally fittedwithin the inner end of the lens housing of the projector;

Figure 9 is a sectional view, taken through the line 9-9 on Figure 8,looking in the direction of the arrows;

Figure 10 is a front face view of a circular mounting for the other endof said sighting element, the same to be frictionally fitted within thefront end of the lens housing of the projector;

Figure 11 is a sectional view, taken through the line I l| l on Figure10, looking in the direction of the arrows; and,

Figure 12 is a rear side elevation of the sight element mounting asotherwise illustrated in Figures 2 and 3.

Referring to the drawings, and more particularly to Figure 1, the lightprojecting components of a standard motion picture projector, asillustrated therein, are comprised in a reflector A, a carbon electrodeholder B, a film aperture element 0, and a lens carrier or housing D; itbeing understood that one of two carbon electrodes (not shown)ordinarily extends horizontally through a central opening in thereflector A and the other likewise through the holder B, the latterbeing carried at the upper end of a vertically disposed arm b and has ascrew clamp c to secure the carbon electrode in place. The lower end ofthe arm b has a screw threaded opening engaged by a complementally screwthreaded shaft d for the adjustment of the electrode, carried by theholder, relatively to the said one electrode which is supported in afixed position in the central opening in the reflector. For the purposesof the present invention, both electrodes are dispensed with until afterthe aligning operation is completed, which operation is efficientlyperformed by means of a visual sight line, preferably a light flexiblewire l0, extended axially from the center opening in the reflector A tothe lens carrier or housing D and through certain cooperativeinstrumentalities presently to be described.

In Figures 1, 2, 3, and 12, a mounting for the rear end of the sightline or wire I9 is shown, and it is comprised in a circular member I4,of a diameter slightly greater than that of the center opening in thereflector, which has its rear side reduced, as at l6, for fittedengagement with said center opening. Formed in spaced relation about anaxial opening 18 in the member [4 are several bores 21), in each ofwhich is mounted a spindle 22 having a latch element 24 on its rear endand an actuating knob 26 on its front end; a coiled spring 28 beinghoused within the bore and encircled about the spindle between the innerend of the knob and an annular shoulder at the inner end of the bore.With the seating of the member M in the reflector opening, the

knobs 26 are turned to swing the latch elements- 24 to positions behindthe edge of the opening where they are firmly held in contact with therear side of the reflector by the tensioning effect of the springs 28 onthe inner ends of the knobs 26. A circular recess 30 is formed in therear face of the member l4, concentrically with respect to the axialopening therein, to house a universal structure, or gimbal, which, asbest shown in Figures 3 and 12, is comprised in an outer annular elementor ring 32 within which is trunnioned, as at 36, a second annularelement or ring 34. Trunnioned, as at 40, horizontally of and Within thesecond element or ring 34 is a cylindrical element 38, which has a bore42 extending diametrically through the same medially between its endsand a V-shaped throat 44 opening into the bore for the insertion intothe latter of the rear end portion of the sight line or wire l0, whichend portion terminates in an enlargement 46, preferably spherical inform, to bear against the inner side of the element 38 to preventaccidental disengagement of the end, when the sight line or wire it! isthreaded forwardly through the opening it for the securement of itsforward end in centered relation within .the lens carrier or housing D,as will presently be explained.

Now referring to Figures 1, 10 and 11, a mounting for the other, orforward, end of the sight line or wire I is shown, and it is comprisedin a circular body 48 which is to be frictienally engaged within thefront end of the lens carrier or housing D. The front side of the bodyi8 is formed with an annular depression surrounding a central.cylindrical portion 53 which has here 52 opening axially through thesame to house the jaws of'a clutch or collet 54, the inner end of ti.bore being reduced and opening through the rear side of the body for thethreading ofthe forward end of the sight line or wire I!) inwardlythereof and. into engagement with the said jaws. Also frictionallyengaged within the rear end of the lens carrier or housing D is acircular plate 56 which has a central aperture 58 opening through thesame in line with the bores in the aforesaid cylindrical element 38 andthe body 43. With the mountings l4 and 48 installed as stated, thesightline or wire In is stretched taut between the same and the forwardend thereof is clamped between the jaws of the clutch or collet 54.

Upon the removal of the electrode from the holder B, and as shown inFigures 1 and 5, it is replaced by an elongated member fidhaving theform of a shuttle, which is provided with an axi a1 bore 62 and aV-shaped throat 64 coextensive therewith and opening into the same tofacilitate its placement on the sight line or wire l0 and, when soplaced, it may be slid along the latter and into position within theholder B; in which position, it will be secured against displacement bythe screw clamp 12, which, in turn, is prevented from being accidentlyloosened by means of a clamp type bracket mounted on the arm 17, thelatter being indicated at B.

In addition to the foregoing aligning instrumentalities, a gauge member88 is provided to cooperate with the sight line or wire [0 and isassociated with the film aperture element C to such end. This gauge isshown in Figures 1, 6 and '7, and is comprised in a flat, relativelythin plate, rectangular in form, and provided with a supporting head illat its top end and an aperture 72, of a. somewhat greater diameter thanthat of the sight line or wire Iii, opening through its exact center andcommunicated by a V-shaped throat '14 opening laterally outward througha side edge of the plate. A rectangular frame 16 is provided on one sideof the member 68 in centered relation with respect to the aperture 12and is disposed within the film aperture C when placed in positionrelative thereto with the sight line or wire it] passing through theaperture 12; the throat 74 allowing for the entry of the sight line orwire into the latter during the placement of the member.

Now, with the described members or devices installed as stated, theperfect alignment of the components of the projector will be indicatedwhen it is ascertained that the sight line or wire i6 is exactlycentered in the bore 62 of the shuttle 60 and the apertures 58 and E2,of the plates 56 and 68, respectively. If, however, such perfection ofalignment is not so indicated, the oifending component of the projectoris to be mechanically adjusted and affixed until the desired accuratealignment is attained.

It is to be here noted that by the employment of the universal, orgimbal, with the member I, the reflector A be readily adjusted aboutitsv axis without in any way affecting the alignment of the sight lineor wire l0. Also, a purpose of'the shuttle 68, other than thatheretofore stated. for the same, is to disclose the accuracy ofalignment of the carbon holding components when the holder B is movedtoward, or away from, the reflector A by a turning motion imparted tothe worm shaft d; a hand crank e being provided at one end of the shaftfor its manipulation.

Having thus fully described a preferred embodiment of my invention, itis to be understood that the words which I have used are words ofdescription rather than of limitation, and that changes within thepurview of the appended claims may be made without departing from thetrue scope and spirit of the invention in its broader aspects.

What I claim is:

1. Means for effecting perfect optical alignment. of the lightprojecting components such as the lens component and film aperturecomponent of a motion picture projector having as its light source afixed carbon electrode and a relatively movable carbon electrode, thefixed electrode being normally supported axially in an opening in thecenter of the light reflector and the movable electrode in an adjustableliolderand in line with the fixed electrode, said means comprising aflexible sighting strand element stretched axially from the center ofthe onening in the reflector to the center of the carrier forthe lenscomponents, said element passing through the electrode opening in theholder from which the electrode has been removed and from thence throughthe film aperture component, a mounting for one end of said elementremovably secured in the said'opening in the reflector from which thefixed electrode has been removed, said mounting including a universalself centering unit with which the said one end of said element iscoupled, and a gripping means for the other end of said elementremovably centered in the lens carrier from which the lens componentshave been removed, the accuracy of alignment of said components beingindicated when the element is observed to pass through the exact centersof the reflector and holder openings and the film aper-' ture.

2. The invention as defined in claim 1, with an elongated member in theform of a shuttle having a longitudinal bore of a slightly greaterdiameter than that of said sighting element and a substantially V-shapedthroat coextensive with said bore and opening laterally outwardtherefrom for the passage of said element therethrcugh and into saidbore, said shuttle being slid along said element after its engagementtherewith and centered within said adjustable.

holder and secured in place by the clamping medium normally employed tosecure the movable electrode therein.

3. The invention as defined in claim 1, with a gauge plate adapted to bepositioned alongside the film aperture component and having an aperturein its center of a lesser area than that of the aperture in the filmaperture component and a slightly greater diameter than that of saidelement and a substantially V-shaped throat opening laterally outwardfrom said aperture through a side edge thereof to facilitate thepositioning of the sighting element in the aperture, and means carriedby said plate to engage in the aperture of said film aperture componentto retain the plate in position with its aperture disposed in the exactcenter of the latter aperture.

4. The invention as defined in claim 1, with the mounting for the saidone end of the sighting element having an axial bore and an overalldiameter slightly greater than that of the opening in the reflector, therear side of said mounting being reduced to have fitted engagement insaid opening, latching means carried by said mounting and adapted to beengaged with the rear side of the reflector about said opening, andmeans carried by said mounting crosswise of the rear end of said borefor the attachment of said sighting element thereto.

5. The invention as defined in claim 1, with the mounting for the saidone end of the sighting element having an axial bore and a recess formedin its rear side concentrically with respect to said bore, a gimbalhoused within said recess, and a horizontal member mounted within theinner element of said gimbal for the attachment of the sighting elementend thereto, said gimbal allowing for the adjustment of the reflectorabout its axis without affecting said sighting element. 6. The inventionas defined in claim 1, with the mounting for the said one end of thesighting element having an axial bore, a horizontal member carried bysaid mounting in rear and crosswise of said bore and having an openingthrough the same in line with the latter, said sighting element havingthe form of a length of a light flexible wire and having its rear endpassing through said bore and said opening, an enlargement on the rearend of said sighting element, said second mounting for the said otherend of said sight line element having an axial bore for the passage ofthe said end therethrough, and a collet mounted on the outer side ofsaid second mounting in line with the axial bore therein to secure thesaid end after said sighting element has been stretched taut to causesaid enlargement to bear against said horizontal member.

WILLARD C. RICORD, SR.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date Re. 17,665 Guillet May 13, 1930 FOREIGN PATENTS Number CountryDate 838,806 France Dec. 16, 1938 OTHER REFERENCES Journal, Soc. Mot.Picture Eng, vol. 21 (August 1933), pages 94-96,

